There is none who is more well-wisher and affectionate to one than his parents. In the abovementioned case, the girl should accept the match selected for her by her parents and she should stay obedient to them. You should discard the thought of marrying the girl from your mind, pairs are destined by Allah. You are wrong to say that her parents have blackmailed emotionally. You should repent to Allah and ask for His forgiveness from your saying: ?I have accepted her as my wife keeping Allah as witness.?
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband